This invention generally relates to systems for controlling pressure in a pressurized system. More particularly, the present invention relates to a cartridge assembly for a valve.
There are many types of systems that process, transmit or use a pressurized fluid. To ensure the safety of these types of systems, each such system typically includes a pressure relief valve designed to prevent the over-pressurization of the system. In an emergency situation, where the fluid in the system reaches an unsafe level, the high pressure of the fluid acts on the pressure relief valve to create an opening to release fluid from the system. Venting fluid to the environment or a safety reservoir through the opening reduces the pressure in the system and prevents another portion of the system from failing due to the high pressure of the fluid.
A common type of pressure relief valve is a rotatable valve assembly. A rotatable valve includes a plug that is mounted on a rotatable shaft and may be rotated between a closed position where the plug blocks the flow of fluid and an open position where the plug allows fluid to flow through the valve. The plug may be mounted on the shaft so that the rotational axis of the plug is offset relative to the center of the plug. Consequently, the pressurized fluid exerts a torque on the shaft and urges the plug to rotate.
Commonly, an activation component such as a buckling pin is operatively coupled to the shaft to prevent the shaft from rotating until the torque on the shaft reaches a certain level indicating that the pressure of the fluid has reached an over-pressure situation. When the pressure of the system reaches a predetermined safety level in such systems, the torque exerted on the valve by the pressurized fluid exceeds the resistance of the pin that keeps the valve from opening. When this event occurs, the pin fails and subsequently the valve opens for the fluid to escape to relieve the pressure in the system.
However, a bare pin used for a pressure relief valve requires considerable care and control during installation. Maintenance personnel must ensure that the bare pin is properly secured and tightened to bear the pressure exerted on the pressure relief valve. Failure to do so may result in untimely opening of the valve. A premature opening below the predetermined safety level leads to an unwanted downtime for the system, while a delayed opening above the predetermined safety level jeopardizes the physical integrity of the system.
Another problem with a bare pin is that there is a risk of pin damage stemming from maintenance personnel having to contact the bare pin during installation or maintenance. This risk of pin damage is especially high for a fragile, low pressure bare pin.
Still, another problem with a bare pin is that the bare pins are difficult to mark with serial numbers and/or certification stamps. Often, a serial number is needed for traceability and control purposes, and industry code certification stamps are needed to indicate a compliance with relevant code requirements. Directly stamping the pins with serial numbers and/or certification stamps will damage the pins.
Yet, another problem with existing systems is that it is a skilled and time consuming activity to remove and reinstall the bare pin. Many times, the bare pin needs to be decoupled from the pressure relief valve for the inspection and maintenance of the system including the pressure relief valve. Due to the risk of pin damage and the caution needed to properly secure and tighten the bare pin, a considerable amount of time is spent in removing and reinstalling the bare pin.
A further problem with existing systems is the need to install bare pins such that they are loaded perfectly along their length axis. Improper pin loading results in loss of set pressure accuracy for the pressure relief device and reduced service life.
In light of the foregoing, there is a need for a device for a pressure relief valve that (1) obviates the care and control needed during installation, (2) reduces the possibility of damaging the activation component during pre-installation storage and shipping, installation, use, and maintenance, (3) decreases the time needed to replace the activation component, (4) enables a complete identification and relevant code stamping of the activation component, (5) reduces the precision required in mounting the pin for proper loading, and (6) provides for the convenient removal and reinstallation of the activation component for valve inspection purposes without impairing its performance characteristics.
Accordingly, the present invention is directed to a device for a pressure relief valve that obviates one or more of the limitations and disadvantages of prior art release devices. The advantages and purposes of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages and purposes of the invention will be realized and attained by the elements and combinations particularly pointed out in the appended claims.
To attain the advantages and in accordance with the purposes of the invention, as embodied and broadly described herein, the invention is directed to a pressure relief device containing a pressurized fluid. The pressure relief device includes a rotatable plug engageable with the system to expose the plug to the pressurized fluid. The fluid acts on the plug to rotate the plug from a closed position to an open position. An activation component is operatively connectible to the plug and is configured to prevent the plug from rotating until a predetermined pressure is exerted on the plug. A cartridge having a hollow body with a first and second end is provided. The hollow body substantially encloses the activation component so that the cartridge and the activation component are replaceable as a unit without any contact with the activation component. A support member is configured to receive the cartridge to operatively connect the activation component with the plug.
In another aspect, the invention is directed to a cartridge assembly for a valve containing a member movable between a first position and a second position. The cartridge assembly includes an activation component operatively connectible with the pressure relief valve. The activation component prevents the member from moving from the first position to the second position until a predetermined pressure is exerted on the valve. The cartridge assembly further includes a cartridge having a hollow body with a first and second end. The hollow body substantially encloses the activation component so that the cartridge and the activation component are replaceable without any contact with the activation component. A support structure engageable with the cartridge is provided to operatively connect the activation component with the valve.
In yet another aspect, the invention is directed to a cartridge for a valve operable between a first configuration and a second configuration. The cartridge includes an activation component operatively connectible with the valve. The activation component maintains the valve in the first configuration until a predetermined pressure is exerted on the valve to force the valve toward the second configuration. The cartridge further includes a hollow body having a first and second end. The hollow body substantially encloses the activation component so that the cartridge is replaceable without any contact with the activation component.
In yet another aspect, the invention is directed to a cartridge for a valve containing a member movable between a first position and a second position. The cartridge includes an activation component operatively connectible with the valve. The activation component maintains the member in the first position. The activation component includes a fusible alloy that liquifies, thereby allowing the member to move toward the second position. The cartridge further includes a hollow body having a first and second end. The hollow body holds the activation component so that the hollow body and the activation component are replaceable as a unit.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.